The present invention relates generally to a motor-fan assembly for a floor cleaning appliance. More particularly, the present invention relates to a motor-fan assembly for a floor cleaning appliance having an improved working air fan, fan chamber, and motor cooling fan housing cover design.
In the floor care appliance art, a motor-fan assembly is typically used in what are known as xe2x80x9cdirty airxe2x80x9d systems as a vacuum source for drawing dirt laden air and/or dirty cleaning solution (both hereinafter referred to as dirty working air) through a nozzle and the fan chamber itself before directing it to a filter bag and/or a receptacle for collection and later disposal. A motor-fan assembly may also be used in what are known as xe2x80x9cclean airxe2x80x9d systems as a vacuum source for creating a suction in the receptacle for drawing the dirt laden air into the receptacle. The floor care appliances referred to include vacuum cleaners of the upright or canister type for vacuuming dirt particles from the floor surface and the extractor type cleaners for scrubbing floors and carpets. Known motor-fan assemblies, therefore, have a working air fan or impeller (hereinafter referred to as working air fan, fan, or impeller) driven by a motor that draws the dirty working air into the fan chamber and expels it through a fan chamber outlet into a receptacle.
In order to meet consumer demand for increased performance in floor care appliances, designers of motor-fan assemblies for such appliances have sought to improve the performance of one or more aspects of the motor-fan assembly. One such aspect is the performance of the working air fan in generating the vacuum source for drawing the dirty air. One other aspect sought to be improved is reducing the noise generated by the working air fan or other parts of the motor-fan assembly. Another aspect sought to be improved is the cooling performance of the motor-fan assembly.
Impellers and fans for use with motor-fan assemblies and the like are well known in the art. There are patents for fans attempting to improve fan performance and reduce noise, fans having spiral blades, and fans less susceptible to impact damage from debris. For example, in U.S. Pat. No. 5,755,555 issued to Swift a rotating fan assembly is provided for use in single stage and multi-stage applications. The fan assembly includes a fan member having a tapered disk member, a flat annular ring member and a plurality of spiral shaped blade members interposed between the disk and the ring. U.S. Pat. No. 5,573,369 issued to Du provides a fan for a vacuum cleaner having a fan housing, a motor and an impeller. The impeller has a hub and multiple blades. The blades have a leading edge that is tapered upward, a top edge that is tapered downward, and a trailing edge that is tapered downward.
However, no patents were found that improve the performance of aforementioned aspects of the motor-fan assembly such as the working air fan, reducing the noise generated by the working air fan or other parts of the motor-fan assembly, or improving the cooling performance of the motor-fan assembly in the manner of the present invention.
Accordingly, an object of the present invention is to improve the performance of a motor-fan assembly for a floor care appliance.
Another object of the present invention is to provide a motor-fan assembly for a floor care appliance with an improved working air fan design.
Yet still another object of the present invention is to provide a motor-fan assembly for a floor care appliance with an improved working air fan that improves debris passage.
Another object of the present invention is to provide a motor-fan assembly for a floor care appliance that reduces working air fan noise.
Yet another object of the present invention is to provide a motor-fan assembly for a floor care appliance with an improved working air fan design that is resistant to impact damage.
These and other objects will be readily apparent to one of skill in the art upon reviewing the following description and accompanying drawings.
The present invention provides an improved motor-fan assembly for a floor cleaning appliance such as a vacuum cleaner or extractor. In one disclosed embodiment, the motor-fan assembly includes a motor housing having a working air inlet, a working air outlet, a working air fan, and a housing cover for the working air fan cavity having a plurality of spiral shaped grooves on the inner surface for reducing noise. The motor-fan assembly further includes a cooling air inlet, a motor cooling air fan, a housing cover for the motor cooling air fan cavity having a plurality of vent openings of a novel design for improved cooling performance. A motor is supported inside the motor housing. A working air fan is positioned between the working air inlet and the working air outlet and is coupled to the shaft of the motor. The working fan draws working air into the motor housing through the working air inlet and blows the working air out of the motor housing through the working air outlet. The plurality of spiral shaped grooves formed on the inner surface of the housing cover covering the working air fan cavity are for reducing the noise generated in the cavity.
In another form of the present invention, a cooling air fan is positioned adjacent the motor and is coupled to the motor shaft. The cooling fan draws cooling air into the motor housing through the cooling air inlet to cool the motor. The cooling air is exhausted to the atmosphere through the plurality of vent openings located in the motor cooling fan housing cover covering the motor cooling air fan cavity. The plurality of vent openings are slot shaped and are spaced circumferentially about the hub of the motor cooling air fan housing cover.
In still another form of the present invention, the working air is generated by a working air fan having a greater number of fan blades compared to conventional fans having five to seven blades. The top edge of the fan blades are parallel to the inner surface of the working air fan cover to improve the passage of debris over the top of the working air fan. The increased number of closely spaced blades also helps prevent debris from getting stuck between the blades.
In an alternate embodiment of the present invention, the motor cooling air fan housing cover has a plurality of vent openings spaced circumferentially about the hub of the housing cover wherein adjacent vent openings are separated by a planar shaped vane. The airstream cooling the motor-fan assembly exits the motor housing through the plurality of vent openings past the planar shaped vanes.